4.2.2.5 TCP Options: RFC-793 Section 3.1

4.2.2.5 TCP Options: RFC-793 Section 3.1

A TCP MUST be able to receive a TCP option in any segment.
A TCP MUST ignore without error any TCP option it does not
implement, assuming that the option has a length field (all
TCP options defined in the future will have length fields).
TCP MUST be prepared to handle an illegal option length
(e.g., zero) without crashing; a suggested procedure is to
reset the connection and log the reason.